856 APPENDIX C. — REPTILES. 



is in great measure destitute of that roughness which is generally 

 associated with the idea of these reptiles. 



The abdominal scales are subquadrangular or lozenge-shaped, 

 either smooth or slightly keeled, according to the species. On 

 the breast and anterior portion of the shoulders several rows of 

 the largest scales are seen, very prominent, very acute posteriorly, 

 and strongly carinated or keeled. The anterior and upper portion 

 of the thigh is likewise provided with large scales, but much less 

 conspicuously keeled than on the shoulders. 



The tail is stout, always depressed at its base : it diminishes 

 very rapidly posterior to the vent, and becomes cylindrical toward 

 its tip. The pyramidal and raised scales are sometimes more con- 

 spicuous on its sides and upper surface than on the body itself. 

 The scales below the tail, in the vicinity of the vent, have the 

 general appearance of those of the belly ; in the post-anal groove 

 some larger scales may occasionally be seen. Here the scales 

 assume a subverticillated arrangement. On the conical portion of 

 the tail they are carinated, while they are generally smooth about 

 the vent. 



The anterior and posterior legs are nearly of equal size ; the 

 latter, however, are slightly stouter. The toes, five in number, 

 are neither short nor very long ; the first and fifth are the shortest 

 and either of equal length, or the fifth may be a little longer ; the 

 second and fourth somewhat longer than the first and fifth, and 

 likewise either of equal length, or the fourth somewhat longer 

 than the second ; the third is always the longest. The scales ex- 

 tend all over the toes, overlapping even the base of the nails : they 

 assume a subtriangular shape, with a very acute posterior summit, 

 and a very distinct carina on their middle. The nails themselves 

 are curved, compressed at the base, and very acute at the tip. 

 On the inferior surface of the hind legs, along the thigh, a series 

 of pores is observed, the femoral pores varying in number and con- 

 spicuousness according to the species. The anal pores are totally 

 absent in phrynosomas. 



We are thoroughly acquainted with six species of the genus 

 Phrynosoma^ viz. Phr. coronatum, Phr. cornutum, Phr. douglassii, 

 Phr. modestum, Phr. orbicular e^ and Phr. platy rhinos. 



Phr. harlani is identical with Phr. cornutum ; Phr. wieg^ 

 manni^ with Phr. orhiculare ; and Phr. hlainvillei^ with Phr* 

 coronatum. 



After a mature examination of Prof. Holbrook's description of 



